Coating machine



June 27, 1939. w. v. SHEARER COATING MACHINE Filed April 22, 1938 2sheets-sheet 1 INVENTOR WLTER VSHEARER BY ATTORNEYS June 27, 1939. w vSHEARER 2 ,163,712

COATING MACHINE Filed April 22, 1938 2 Sheets-Sheet 2 INVENTOR MATE?767/5425? W01 ea ATTORNEY Patented June 27, 1939 UNITED STATES PATENTOFFICE OO ATING MACHINE Application April 22, 1938, Serial No. 203,523

4 Claims.

This invention relates to a machine for coating webs of paper and thelike, and more particularly to a machine for coating such webs with athermo-plastic material.

Substantial dimculties have been encountered in applying coatings ofthis character to webs of paper and the like. The coating must beapplied at a relatively high temperature, it must then be brought to asmooth uniform surface before it sets sufficiently to be unworkable andthe whole operation must be carried out with suiiicient rapidity to becommercially practical.

It is the object of my invention to provide a machine which will meetthe above requirements a in commercial operation.

In the following specification my invention is described as embodied ina machine particularly adapted to the application of alkyl resincoatings, but it will be understood that its principles are goapplicable to work with other similar thermoplastics.

In the accompanying drawings which illustrate one embodiment of myinvention,

Fig. 1 is a side elevation of the machine;

35 Fig. 2 is a sectional view substantially on line 2-2 of Fig. 1;

Fig. 3 is' a sectional view substantially on line 3 3 of Fig. 1;

Fig. 4 is a detail plan view, on a larger scale,

39 of the drive for the doctor blade;

- Fig. 5 is a detail sectional view, on a larger scale, substantially online 6-5 of Fig. 2; and

Fig. 6 is a detail sectional view, on a larger scale, substantially online 6-6 of Fig. 3.

35 Referring to the drawings, in designates a table-like frame uponwhich the variousinstru- 45 pressed by a rubber covered roll is. Rollsl6 and ll are journaled in suitable brackets secured to frame It, thebearings of roll i9 being adjustably mounted in the brackets formovement toward and from roll l8 through a handwheel 2| 60 in a wellknown manner, whereby the degree to which the paper is pressed againstroll I3 may be adjusted. I

I Roll I8 dips into a tank 23 containing the ther-' moplastic coatingmaterial. Both the roll l3 and 35 tank 23 are heated to maintain thecoating material in a sufficiently fluid condition for proper operation.While any suitable heating means may be employed, I prefer to constructthe tank with double walls forming a jacket and to circulate Dowtherm atdesired temperature through 5 the roll and jacket. The preferredDowtherm is an eutectic mixture of the organic compounds,

. diphenyl and diphenyloxide, the composition of the mixture beingdiphenyl (CsH5)z-26 /2%. and diphenyloxide (CaH5)2O--73 /2%. It isliquid at 10 ordinary room temperatures, freezes at 53.6 F. and boils at500 F. at atmospheric pressure. The Dowtherm is supplied to the roll andjacket by pipes and 26, respectively, which connect to a supply line 21leading from a boiler not 13 shown. The return pipes from the roll andjacket are shown in Fig. 2 at 23 and 23 respectively, which connect to areturn line not shown. I have found Dowtherm of particular advantage inproviding the relatively high temperatures re- 20 quired, and which mustbe uniformly maintained within quite narrow limits to secure asatisfactory product.

The printing or coating roll it is intaglio engraved to provide aplurality of small closely arranged pockets which deposit or print thecoating material as a plurality of dots on the web as the latter passesover the roll. In order to control the depth to which the roll it! dipsinto tank 23 the latter is mounted as shown in Fig. 2 on vertical racks33 reciprocably mounted in guides 3| mounted on frame to. Gears 32secured to a shaft 3 engagethe racks 30 and shaft 33 is provided with ahandwheel 34 by which shaft 33 may be rotated to raise or lower tank 23.The 35 supply and return pipes 26 and 29 are provided with flexiblesections, one of which is shown at 35, to accommodate the adjustment ofthe tank.

The supply and return pipes 25 and 28 communicate with the interior ofroll i8 through 40 shaft 33 on which the roll is secured and the latteris rotated in the direction of the arrow, ,Fig. 1, by a helical gear 33secured to shaft 38 and meshing with a gear 40 secured to the main driveshaft 4i.

Surplus material is removed from the surface of roll l8 by means of adoctor blade 42 provided at its ends with studs 43 pivotally andslidably mounted in bearing guides 44 secured to brackets 20. The doctor42 is reciprocated longitudinally of the roll by means of a link 46, oneend of which is pivoted to the doctor at 41. The other end of link 46 ispivoted at 48 to a block adjustably secured in a slot 50 formed in acrank disk 5|. Disk 6| issecured to the upper end of a vertical shaft 52journaled in a bearing bracket 58 and provided with a worm gear 5|. Thelatter meshes with a worm 55 secured to main drive shaft ll. The gearratios are made such that the doctor 42 reciprocates at a relativelyhigh rate of speed for reasons later pointed out. The doctor 42 isyieldingly held against the surface of roll I8 by any suitable meanssuch as a weight 51 connected to one end of cables 58 which pass overidle pulleys 59, and are secured to the outer end of arms 6|! extendingfrom the studs 43 of the doctor blade.

From the printing roll it the web passes beneath an idle guide roll 62journaled in bearings 63 slidably mounted in arms 64 of spaced brackets65 secured to the frame Ill. The bearings 58 are adjusted in desiredposition in the arms 64 by means of screws 89. From the idler 62 the webpasses over a smoothing roll 88 journaled in the brackets 65. Roll 68 isinteriorly heated by means of inlet and outlet pipes Ill and II enteringthe roll through its shaft I2 and connected to the previously mentionedsystem through which Dowtherm is circulated. The flow of Dowthermthrough the rolls I8 and 58 is controlled by suit;- able valves 59positioned in their inlet pipes. The roll 68 is driven in a directionreverse to that of the web travel, as shown by the arrow in Fig. 1, bymeans of a spiral gear I3 (Fig. 3) secured to one end of shaft I2, anddriven from shaft ti through a variable speed gear unit indicated at itin Fig. 3. The extent of the surface of roll is engaged by the web maybe varied by the vertical adjustment of idle roll 62.

Beyond the smoothing roll 68 is positioned a stationary smoothing unitgenerally indicated at it. This unit comprises a pair of spaced members76 with which the coated surface of the web successively engages afterleaving roll 68.

As best shown in Fig. 6, the members I5 have surfaces of varyingcurvature and depending on the angular relation of the members to theweb make a greater or less surface contact with the web. The characterof the action of the members I on the coating also varies with theangular position of the member, the spreading action as distinguishedfrom a smoothing or burnishing action increasing when the members aremoved clockwise, as viewed in Fig. l, to increase the action of therelatively sharp edge of the heel portion TI. The member I6 gives a veryeflicient control of the coating operation, and while the angularsetting of these members is rather critical their proper position iseasily determined in any given case by observation of the coatedsurface.

The members I8 are secured by machine screws I8 to supporting bars 19which in turn are carried by rock shafts 80 to which the bars aresecured by machine screws Ill. The shafts 80 pivctally engage in bearingmembers 82 and are held in adjusted angular position therein by nuts 83threaded on the ends of the shafts. The bearing members 82 are mountedon a shaft 84, the ends of which are supported in blocks 85 verticallyslidable in arms 86 of bracket 55 by means of adjusting screws 91. Shaft84 is held in adjusted angular position in the blocks 85 by nuts 89threaded on the end of the shaft.

The members I6 are heated by electric heat-. ing units 90 positioned inbores 9I extending lengthwise of the members.

From the members 16 the web inclines downwardly and beneath a coolingdrum 95. In its passage from members 16 to drum 95 the web passes overan auxiliary heating unit comprising two parallel spaced gas heatingunits 98 mounted on a bracket 91 extending from a block 98 slidablymounted in guides 99 and movable thereon by means of screws It!) wherebythe distance of units 96 from the web may be adjusted. Gas is suppliedto heaters 99 by flexible pipes ID! from any suitable source not shown.The flow of gas is controlled by valves I92 placed in the pipes I I.

Just prior to its contact with drum 95 the coated surface of the web issubjected across its width to a blast of cooling air delivered through asuitable conduit I03 by a blower I04. Drum 95 is journaled in suitablebearings formed in brackets I mounted on frame I0. Any suitablerefrigerating fluid is supplied to the interior of the drum throughpipes I08 from a source not shown. The web is drawn through the machineand around drum 95 by drawing rolls I08 and I09 between which the webpasses from drum 95. Drum 95 and roll I09 are driven by suitablegearing, not shown, from shaft 4|. The bearings of roll I98 are slidablymounted in guides I I0 for adjustment toward and from roll I99 by meansof screws III.

From rolls I08Iil9 the web passes around guide rolls M2 to any suitablewind-up mechanism.

Shaft 4| may be driven in any suitable manner, as shown, power beingsupplied through a series of V-belts from a motor, not shown.

Thermo-plastic coatings such as alkyl resins are quite difiicult tohandle and require careful control at the various stages. Thetemperature of the material, its consistency at the various operationsand its physical manipulation are relatively critical if a satisfactoryproduct is to be obtained.

The material sets rapidly and there is atendency for blemishesand localinequalities in thickness to persist. For example, it is almostimpossible under working conditions to prevent occasional particles ofmatter from lodging under the edge of the doctor blade 42 producing finelines or scratches in the coating. These scratches are difficult tosmooth out. I have found. however, that by reciprocating the doctorblade more rapidly with respect to the travel of the web than is commonpractice with conventional coatings, that the scratches, if and whenthey occur, assume a zig-zag path of substantial angularity and thatunder these conditions the scratches can be obliterated by roll 68 andmembers I6. I

It will further be seen that the temperature of the material at the timeof its application and at each stage of its manipulation is undercontrol and that the extent of contact of the web with roll 68 can beadjusted. The character of the manipulation by members I6 is also underthe control of the operator. Further, controlled heaters 96 may be usedwhen necessary to render the setting of the coating more gradual and produce a finer and glossier surface texture in the finished product.

By proper setting of tension rolls I5 and drawing rolls IOU-I09 thedesired tension in the web may be maintained.

By suitably arranging the intaglio pattern on roll l8 the coating may beapplied in stripes or patches of desired form as is sometimes desirablein coating labels or wrappers in web formylater to be cut to desiredshape.

I claim:

1. A machine for applying thermo-plastic coatings to webs of paper andthe like which comprises means to advance the web, a reservoir for thecoating material, means to maintain the material in the reservoir atconstant temperature, an intaglio printing roll for transferringmaterial from the reservoir to the web, means to heat the printing roll,a doctor blade for removing surplus material from the printing roll,means to reciprocate the blade at a rate sufllcient to give substantialangularity to any streaks caused by foreign particles under the doctorblade, a reversely rotating heated smoothing roll engaging the coatedsurface of the web, a heated smoothing bar having a surface of varyingcurvature over which the web is drawn, means to adjust the area ofengagement of the web with the smoothing roll, means to adjust theangularity of the smoothing bar with respect to the surface of the web,means to cool the coating on the web, and means to control thetemperature of the web during its passage from the smoothing bar to thecooling means.

2. A machine for applying thermo-plastic coatings to webs of paper andthe like, which comprises, means to advance the web, a reservoir for thecoating material, means to maintain the material in the reservoir atconstant temperature, an intaglio printing roll for transferringmaterial from the reservoir to the web, means to heat the printing roll,a doctor blade for removing surplus material from the printing roll,means to reciprocate the blade at a rate suflicient to give substantialangularity to any streaks caused by foreign particles under the doctorblade, a reversely rotating heated smoothing roll engaging the coatedsurface of the web, a heated smoothing bar having a surface of varyingcurvature over which the web is drawn, means to adjust the area ofengagement of the web with the smoothing roll, means to adjust theangularity of the smoothing bar with respect to the surface of the web,and means to cool the coating on the web.

3. A machine for applying thermo-plastic coatings to webs of paper andthe like which comprises means to advance the web, a reservoir for thecoating material, an intaglio printing roll for transferring materialfrom the reservoir to the' web, a reversely rotating smoothing rollengaging the coated surface of the web and a common heating system forthe reservoir, printing roll and smoothing roll through which Dowthermis constantly circulated.

4. A machine for applying thermo-plastio coatings to webs of paper andthe like which comprises means for advancing the web, means for applyingthe material in a hot plastic condition to the material in the form ofsmall closely adjacent dot formations, reversely rotating means andstationary bar means for spreading the dots into a smooth thin coatingand means to maintain the material in proper plastic condition from thetime of its first application until the completion of the spreadingoperations.

WALTER V. BEAM.

